In this study, we investigate how cloud properties such as phase, liquid water content, and droplet effective radius are altered due to aerosols originating from mostly anthropogenic pollution. In situ aircraft observations obtained from June to September 2015 during the Atmospheric Radiation Measurement (ARM) Airborne Carbon Measurements (ARM-ACME-V) field campaign are used to characterize the aerosol and cloud properties. For this, the Gulfstream-1 aircraft was equipped with a wide range of instruments to sample cloud particles (e.g., Fast Cloud Droplet Probe (FCDP), 2D Stereo Particle Imaging Probe (2DS), High Volume Precipitation Spectrometer (HVPS)), aerosols (e.g., nephelometer, Condensation Particle Counter (CPC), Passive Cavity Aerosol Spectrometer (PCASP)) and trace gases (e.g., carbon monoxide). These in situ measurements are complemented by ground-based remote sensing cloud instruments (cloud radar, radiometer, and lidar) located at the two ARM sites on the North Slope of Alaska (Barrow and Oliktok Point). Additional surface observations at these sites enabled us to examine how meteorological and surface conditions influence the impact of aerosols on cloud properties.
Comparisons of data collected at these two sites are of particular interest due to the different characteristics with respect to anthropogenic aerosol background: While Oliktok Point is surrounded by petroleum production facilities, Barrow represents a more pristine environment.